Reducing a data storage device readying time

ABSTRACT

A data storage device includes a first memory section with a reserved area having stored therein an event trigger log that includes a history of past logged events. The data storage device also includes a second memory section separate from the first memory section. The data storage further includes a controller that, upon power up of the data storage device and before the data storage device is ready to receive host commands, allocates a buffer in the second memory section for capturing new events. The controller postpones linking of any captured new events with the past logged events until at least after the data storage device is ready to receive the host commands.

BACKGROUND

Data storage devices are typically included in systems having one ormore host computers. Examples of data storage devices include hard diskdrives (HDDs), which are electromechanical devices containing spinningdisks and movable read/write heads, solid state drives (SSDs), which usememory chips and contain no moving parts, and hybrid drives, whichcombine features of HDDs and SSDs in one unit.

SUMMARY

In one embodiment, a data storage device is provided. The data storagedevice includes a first memory section with a reserved area havingstored therein an event trigger log that includes a history of pastlogged events. The data storage device also includes a second memorysection separate from the first memory section. The data storage furtherincludes a controller that, upon power up of the data storage device andbefore the data storage device is ready to receive host commands,allocates a buffer in the second memory section for capturing newevents. The controller postpones linking of any captured new events withthe past logged events until at least after the data storage device isready to receive the host commands.

In another embodiment, a method is provided. The method includesstoring, by a control circuit of a data storage device, an event triggerlog including a history of past logged events of the data storage devicein a reserved area included in a first memory section of the datastorage device. The method also includes, upon power up of the datastorage device and before the data storage device is ready to receivehost commands, allocating a buffer in a second memory section, of thedata storage device, for capturing new events in the data storagedevice. The method further includes postponing linking of any capturednew events with the past logged events until at least after the datastorage device is ready to receive the host commands.

In yet another embodiment, a data storage device is provided. The datastorage device includes a system memory. The data storage also includesa controller that, upon power-on reset of the data storage device andbefore the data storage device is ready to receive host commands,allocates a buffer in the system memory for capturing new events. Thecontroller links any captured new events with past logged events afterthe data storage device is ready to receive the host commands.

This summary is not intended to describe each disclosed embodiment orevery implementation of the techniques for reducing a data storagedevice readying time described herein. Many other novel advantages,features, and relationships will become apparent as this descriptionproceeds. The figures and the description that follow more particularlyexemplify illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example apparatus having a data storagedevice in accordance with one embodiment.

FIG. 2 is a flow diagram of a method of reducing a data storage devicereadying time in accordance with one embodiment.

FIG. 3 is a block diagram illustrating and example structure of an eventtrigger log entry in accordance with one embodiment.

FIG. 4 is a block diagram of a hard disc drive that employs a method ofreducing readying time in accordance with one embodiment.

FIG. 5 is an isometric view of a solid-state drive that employs a methodof reducing readying time in accordance with one embodiment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the disclosure generally relate to reducing a datastorage device readying time.

Data Storage devices include a logging mechanism (e.g., an event triggerlog) to capture device information when certain events (e.g., read/writefailures) occur. The event trigger log may be used by the manufacturerto carry out failure analysis for the device failure in the field ordata analysis on the drive behavior.

Conventional data storage devices load the event trigger log, includinga history of past logged events, form a reserved memory area to a systembuffer memory as part of the drive power up initialization. This iscarried out because it enables immediate linking of any newly capturedevents with the previously logged events, thereby maintaining a singlesequence of logged events. However, loading of past logged events atpower up may impact the device initialization time or TTR (time toready) especially when the size of the event trigger log is large (e.g.,in high capacity devices and devices with complex designs includingshingled magnetic (SMR), interlaced magnetic recording (IMR), etc.).

To help reduce TTR, embodiments of the disclosure postpone loading ofthe past logged events into the system buffer memory until at leastafter the data storage device is ready to receive host commands. In oneembodiment, upon power up of the data storage device and before the datastorage device is ready to receive host commands, a buffer is allocatedin the system memory for capturing new events. The step of loading thepast logged events into the system buffer memory is eliminated from thepower-up sequence. Any captured new events in the buffer are linked withthe past logged events at a later time (e.g., when the data storagedevice enters into an idle state). This reduces TTR. An example of adata storage device in which loading of the past logged events into asystem buffer memory is postponed until at least after the device isready to receive host commands is described below in connection withFIG. 1.

It should be noted that the same reference numerals are used indifferent figures for same or similar elements. It should also beunderstood that the terminology used herein is for the purpose ofdescribing embodiments, and the terminology is not intended to belimiting. Unless indicated otherwise, ordinal numbers (e.g., first,second, third, etc.) are used to distinguish or identify differentelements or steps in a group of elements or steps, and do not supply aserial or numerical limitation on the elements or steps of theembodiments thereof. For example, “first,” “second,” and “third”elements or steps need not necessarily appear in that order, and theembodiments thereof need not necessarily be limited to three elements orsteps. It should also be understood that, unless indicated otherwise,any labels such as “left,” “right,” “front,” “back,” “top,” “bottom,”“forward,” “reverse,” “clockwise,” “counter clockwise,” “up,” “down,” orother similar terms such as “upper,” “lower,” “aft,” “fore,” “vertical,”“horizontal,” “proximal,” “distal,” “intermediate” and the like are usedfor convenience and are not intended to imply, for example, anyparticular fixed location, orientation, or direction. Instead, suchlabels are used to reflect, for example, relative location, orientation,or directions. It should also be understood that the singular forms of“a,” “an,” and “the” include plural references unless the contextclearly dictates otherwise.

FIG. 1 is a block diagram of an example apparatus 100 that includes adata storage device 102 in accordance with one embodiment. Data storagedevice 102 includes a storage controller or control circuit 106 thatcommunicatively couples a storage tier 108 to a host 104 via a hostinterface 122. In an implementation, the storage tier 108 is a dynamicstorage tier. The storage controller 106 provides a mechanism to allowthe host 104 to store data to and retrieve data from the storage tier108. In an implementation, the storage tier 108 may be a main datastore. The storage tier 108 may include without limitation one or moreof magnetic data storage discs, optical data storage discs, non-volatilerandom access memory (RAM), such as NAND flash memory and a volatile RAMstorage medium such as dynamic random access memory (DRAM). The storagetier 108 may include a reserved area 109 in which an event trigger logcomprising a history of past logged events may be stored.

The storage controller 106 may utilize communication interfaces andprotocols including SATA (serial advanced technology attachment), SCSI(small computer system interface), eSATA (external serial advancedtechnology attachment), SAS (serial attached SCSI), USB (universalserial bus), and others to communicate with the host 104 via the hostinterface 122. The storage controller 106 also includes an eventmanagement module 110, that includes program code having instructions tocapture and log events in a manner that helps minimize TTR.

As can be seen in FIG. 1, the storage controller 106 also includes amemory 124 that may be used for storing data and/or one or more modulessuch as 110 in some embodiments. It should be noted that, in differentembodiments, module 110 may comprise hardware, software and/or firmware.In one embodiment, the memory 124 may serve as a system memory in whicha buffer may be allocated for capturing new events. In otherembodiments, a separate memory or memory section 127 may serve as thesystem memory in which the buffer for capturing new events is allocated.The storage controller 106 further includes a processor 128. Theprocessor 128 may perform functions of the storage controller 106including functions disclosed herein as performed by module 110. Theprocessor 128 may execute instructions stored on non-transitory computerreadable media to perform the functions of the storage controller 106.

In one embodiment, module 110 may include multiple sub-modules. Thesub-modules may include a new event handling module 130, an eventhistory log loading module 132 and an event log integration and updatemodule 134. Upon power-on reset of the data storage device 102 andbefore the data storage device 102 is ready for host commands, the newevent handling module 130 allocates a buffer for capturing new eventsand helps store new events on the allocated buffer. The event historylog loading module 132 enables loading of the event history log from thereserved area 109 into a buffer in the system memory any time after thedata storage device 102 is ready for host commands (e.g., when the datastorage device 102 enters a power saving mode (e.g., an idle state),when the host 104 requests event log information form the data storagedevice 102, before the data storage device is powered down, etc.). Theevent log integration and update module 134 mergers the newly capturedevents with the event history log data and updates the reserved area 109with the merged information.

FIG. 2 is a flowchart showing an event trigger logging method 200carried out in a data storage device (such as 102 of FIG. 1) inaccordance with one embodiment. The method starts at 202. At block 204,data storage device power up initialization is carried out. The devicepower up initialization may involve performing a sequence of operationsthat help the data storage device transition from a lower operationalstate (e.g., an “off” state) to a higher operational state. At block206, a buffer is allocated to capture new events (e.g., futureread/write operation failure events). Once the buffer is allocated, atblock 208, the data storage device is ready to receive host commands(e.g., commands from host 104 of FIG. 1). At block 210, a host command(e.g., a read/write command received in the data storage from the host)is processed with the help of a control circuit/processor (such as 128of FIG. 1). At block 212, a determination is made (e.g., by a controlcircuit or processor such as 128 of FIG. 1) as to whether the hostcommand was properly processed (e.g., without errors) or whether anevent (e.g., a command processing error) occurred. If no event occurred,control is returned to block 208. If an event occurred, at block 214,information related to the event is logged in the event buffer, whichwas allocated at block 206. Also, at block 214, if the logged event is afirst event or initial event saved in the buffer, a new events flag isset (e.g., set to “1”) in the event buffer. The new events flag may beset once in the event buffer to indicate (e.g., to controller circuit orprocessor 128 of FIG. 1) the presence of one or more new events in theevent buffer, which have not been merged into the event history log.

As block 216, a decision is made as to whether the one or more newevents logged in the event buffer should be saved (e.g., written to thereserved area 109 of FIG. 1). The decision to save the one or more newevents logged in the event buffer may be made based on an operationalstate of the data storage device (e.g., when the data storage device isin an idle state), based on whether a command from the host requestingevent log information form the data storage device is received in thedevice, or whether the data storage device is going to be powered down.If a decision not to save the one or more new events is made at block216, control returns to block 208. If a decision to save the one or morenew events is made at block 216, control passes to block 218. At block218, an event history log is loaded from, for example, a reserved area(e.g., reserved area 109 of FIG. 1) into a system memory of the datastorage device (e.g., memory 127 of FIG. 1). At block 220, the newlylogged events are merged into the event history log. The may involvingindexing the newly logged events to provide a proper time-ordered eventsequence in the merged event history log. Upon merging the newly loggedevents into the event history log, the new events flag may be cleared(e.g., set to “0”) in the event buffer to indicate that there are nopending new events to be merged. At block 222, the merged/updated eventhistory log is saved into, for example, the reserved area (e.g.,reserved area 109 of FIG. 1). At block 224, a determination is made asto whether the data storage device is to be powered down. If the datastorage device is not to powered down, control passed to block 208. Ifthe data storage device is to be powered down, the process ends at 226.

FIG. 3 is a block diagram illustrating and example structure of an eventtrigger log entry 300 in accordance with one embodiment. In the exampleof FIG. 3, event trigger log entry 300 includes a timestamp field 302,an address (e.g., logical block address (LBA)) field 304, an event/errorcode field 306 and a temperature field 308. It should be noted that theevent trigger log fields in FIG. 3 are a non-limiting example and anysuitable event trigger log entry 300 fields may be used in differentembodiments. Timestamp filed 302 is used to store a time when anevent/error occurs. Address field 304 is utilized to store a LBAassociated with a location of the event/error. Event/error code field306 is used to store a code that is associated with the event/error, andtemperature field 308 is used to store a device temperature when theevent/error occurs.

The following are a few simplified examples for event trigger logging:

1) Unrecoverable Disc Error (UDE) Detected

Here, the data storage device encounters a UDE while processing a readcommand. Upon encountering the UDE, the time at which the UDE occurredis stored in timestamp field 302, a location (e.g., LBA) at which theUDE occurred is stored in address field 304, an error code associatedwith UDE is stored in event/error code field 306 and the devicetemperature when the UDE occurred is stored in temperature field 308.

2) Large Shock Detected

Here, the data storage device encounters a relatively large shock whenit is in operation. Upon detecting the shock, the time at which thelarge shock occurred is stored in the timestamp field 302. However,since the shock is at the device level, there is no specific location inthe device associated with the shock. Thus, the address field 304 is notapplicable. Similarly, the event/error code field 306 and thetemperature field 308 and not applicable for the shock event.

3) IOEDC (Input/Output Error Detection and Correction Checksum) ErrorDetected

Here, data corruption along a data path is detected during a read or awrite operation in the data storage device. Upon detecting the IOEDCerror, the time at which the IOEDC error occurred is stored in timestampfield 302, a location (e.g., LBA) at which the IOEDC error occurred isstored in address field 304 and the device temperature when the erroroccurred is stored in temperature field 308. No event/error code isstored in field 306 for this event.

4) SMART (Self-Monitoring, Analysis and Reporting Technology) Trip

Here, a SMART trip is detected during operation of the data storagedevice. Upon detecting the SMART trip, a time at which the SMART tripoccurred is stored in timestamp field 302, an attribute number thatcaused the trip is stored address field 304, an error code for the SMARTtrip is stored in event/error code field 306 and the device temperaturewhen the SMART trip occurred is stored in temperature field 308.

FIG. 4 shows a block diagram of the disc drive 400 that employs a methodof reducing readying time in accordance with one embodiment. Disc drive400 is a particular example of a data storage device 102 (of FIG. 1). Aswill be described in detail further below, in one embodiment disc drive400 employs one or more discs on which multiple data tracks may bewritten in a partially-overlapping shingled pattern, with eachsuccessive track overwriting a portion of the previous track. In anotherembodiment, disc drive 400 employs one or more discs on which no datatracks are written in a partially-overlapping shingled pattern.

Disc drive 400 is shown in FIG. 4 to be operably connected to a hostcomputer 402 in which disc drive 400 may be mounted. Disc drive 400includes a microprocessor system 404 that generally provides top levelcommunication and control for disc drive 400 in conjunction withprogramming for microprocessor system 404 stored, for example, inmicroprocessor memory 406. Disc drive 400 may communicate with hostcomputer 402 using a bus 408.

Memory 406 can include RAM, read only memory ROM, and other sources ofresident memory for microprocessor 404. Disc drive 400 includes one ormore data storage discs 412. Discs 412 are rotated at a substantiallyconstant high speed by a spindle control circuit 414. One or more heads416 communicate with the surface(s) of discs 412 to carry out dataread/write operations. The radial position of heads 416 is controlledthrough the application of current to a coil in an actuator assembly417. A servo control system 420 provides such control.

As noted above, in some embodiments, tracks may be written on one ormore storage discs 412 in a partially-overlaying relationship. Theoverlaying of tracks is shown in close-up view of area 422 of disc(s)412. In area 422, a corner of head 416A is shown writing a track portion424. Different shading within the track portion 424 represents differentmagnetic orientations that correspond to different values of storedbinary data. The track portion 424 is overlaid over part of trackportion 425. Similarly, track portion 425 is overlaid over part ofportion 426, portion 426 is overlaid over portion 427, etc.

The portions 424-427 may be part of what is referred to herein as aphysical band which, in this embodiment, may include tens, hundreds orthousands of similarly overlapping, concentric portions 424-427. Gapsare created between such physical bands so that each physical band canbe updated independently of other physical bands. The overlaying ofsuccessive track portions within a physical band in shingled magneticrecording (SMR) means that individual parts of the physical band may notbe randomly updated on their own. This is because spacings betweencenters of track portions 424, 425, 426, 427, for example, are smallerthan a width of a write pole (not separately shown) of head 416.However, a width of a reader (not separately shown) of head 416 may besmall enough to read individual track portions 424, 425, 426, 427,thereby enabling random reads of data to be carried out.

In certain embodiments, disc drive 400 includes a memory 428 that mayserve as, for example, a first/upper level cache denoted by referencenumeral 428A. In some embodiments, memory 428 is physically separatefrom discs 412. The memory 428 may be of a different type than the discs412. For example, in certain embodiments, memory 428 may be constructedfrom solid-state components. In one embodiment, memory 428 may be aFlash memory.

In some embodiments, the one or more storage discs 412 are managed asnon-overlapping disc portion 430 and disc portion 435. In someembodiments, disc portion 430 is used for a second level cache denotedby reference numeral 430A and disc portion 435 serves as a main storedenoted by reference numeral 435A. In an alternate embodiment, each ofthe first level cache 428A, the second level cache 430A and the mainstore 435A may be allocated from a pool of memory locations thatincludes, for example, storage locations from memory 428 and storagelocations or physical bands from storage discs 412. Dashed box 427 ofFIG. 4A indicates that, in the alternate embodiment, the entire set ofstorage locations that constitutes the storage space supplied by disc(s)412 and memory 428 in disc drive 400 may be organized for three uses,namely the first level cache 428A, the second level cache 430A and mainstore 435A.

In the embodiment of FIG. 4A, disc drive 400 may use memory 428 inconjunction with disc portion 430 in order to manage data as the data isbeing transferred to main storage locations 435 on disc(s) 412. In theinterest of simplification, components such as a read/write channelwhich encodes data and provides requisite write current signals to heads416 is not shown in FIG. 4A. Also, any additional buffers that may beemployed to assist in data transfer to the memory 428 and the mainstorage locations 435 are not shown in the interest of simplification.

As noted above, SMR may be used for storage in disc portion 430, whichserves as second-level cache 430A. Also, as can be seen in FIG. 4A, mainstorage locations 435 are on a same data storage medium as thesecond-level cache locations 430. Thus, in the embodiment of FIG. 4A,second-level cache 430A is a media cache.

A SMR media cache such as 430A may rely on a high cleaning throughput toimprove the host write throughput. As indicated above, in high capacitydevices and devices with complex designs including SMR, an event triggerlog/event history log stored in, for example, a reserved area 109 ofportion 435 of disc 412 may be large. To help reduce TTR in disc drive400, embodiments of the disclosure postpone loading of the past loggedevents from event trigger log/event history log stored in reserved area109 into a system buffer memory (e.g., memory 428). This may be carriedout by modules 130, 132 and 134 the may be part of microprocessor system404 or may be separate components coupled to microprocessor system 404.Modules 130, 132 and 134 operate in a manner described above inconnection with FIG. 1 and carry out TTR reduction operations in amanner described in connection with FIG. 1. Therefore, in the interestof brevity, a detailed description of modules 114 is not repeated inconnection with FIG. 4.

FIG. 5 illustrates an oblique view of a solid state drive (SSD) 500 thatemploys a method of reducing readying time in accordance with oneembodiment. SSD 500 includes one or more circuit card assemblies 502 andtypically includes a protective, supportive housing 504, a top cover(not shown), and one or more interface connectors 506. SSD 500 furtherincludes a controller ASIC 508, one or more non-volatile memory devices510, and power regulation circuitry 512. The memory devices 510 areessentially the SSD's data storage media for the caches and main store.In some applications, SSD 500 further includes a power-backup energystorage device, such as a super-capacitor 514.

In accordance with certain aspects, the solid-state drive 500 includes acircuit card assembly 502 that includes a connector 506 for connectionto a host computer. In accordance with certain aspects, the connector506 includes a NVMe (non-volatile memory express), SCSI, SAS, FC-AL(fiber channel arbitrated loop), PCI-E (peripheral componentinterconnect express), IDE (integrated drive electronics), AT (advancedtechnology), ATA (advanced technology attachment), SATA, IEEE (instituteof electrical and electronics engineers)-1394, USB or other interfaceconnector adapted for connection to a host.

If, as shown in FIG. 5, more than one non-volatile memory device 510 isincluded in SSD 500, then one of the non-volatile memory devices 510 maybe used as the first level cache. Physical storage locations (forexample, erasure blocks) in the other one or more non-volatile memorydevices 510 may be utilized as second level cache and as main storagelocations. In other embodiments, physical storage locations in the oneor more non-volatile memory devices 510 may serve a pool of physicalbands for assignment to first level cache, second level cache and mainstorage. In SSD 500, controller ASIC 508 may include modules 130, 132and 134 that operate in a manner described above. Further an eventtrigger log/event history log may be stored in a reserved area in one ofnon-volatile memory devices 510, and a new event buffer may be allocatedin another one non-volatile memory device 510. In some embodiments, thereserved area having the event trigger log/event history stored thereinand the new event buffer may be in different sections of a same memory.

In accordance with various embodiments, the methods described herein maybe implemented as one or more software programs running on one or morecomputer processors or controllers, such as those included in devices100, 400 and 500. Dedicated hardware implementations including, but notlimited to, application specific integrated circuits, programmable logicarrays and other hardware devices can likewise be constructed toimplement the methods described herein.

The illustrations of the embodiments described herein are intended toprovide a general understanding of the structure of the variousembodiments. The illustrations are not intended to serve as a completedescription of all of the elements and features of apparatus and systemsthat utilize the structures or methods described herein. Many otherembodiments may be apparent to those of skill in the art upon reviewingthe disclosure. Other embodiments may be utilized and derived from thedisclosure, such that structural and logical substitutions and changesmay be made without departing from the scope of the disclosure.Additionally, the illustrations are merely representational and may notbe drawn to scale. Certain proportions within the illustrations may beexaggerated, while other proportions may be reduced. Accordingly, thedisclosure and the figures are to be regarded as illustrative ratherthan restrictive.

One or more embodiments of the disclosure may be referred to herein,individually and/or collectively, by the term “invention” merely forconvenience and without intending to limit the scope of this applicationto any particular invention or inventive concept. Moreover, althoughspecific embodiments have been illustrated and described herein, itshould be appreciated that any subsequent arrangement designed toachieve the same or similar purpose may be substituted for the specificembodiments shown. This disclosure is intended to cover any and allsubsequent adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the description.

The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b) and is submitted with the understanding that it will not be usedto interpret or limit the scope or meaning of the claims. In addition,in the foregoing Detailed Description, various features may be groupedtogether or described in a single embodiment for the purpose ofstreamlining the disclosure. This disclosure is not to be interpreted asreflecting an intention that the claimed embodiments employ morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter may be directed toless than all of the features of any of the disclosed embodiments.

The above-disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments, which fall withinthe true spirit and scope of the present disclosure. Thus, to themaximum extent allowed by law, the scope of the present disclosure is tobe determined by the broadest permissible interpretation of thefollowing claims and their equivalents, and shall not be restricted orlimited by the foregoing detailed description.

What is claimed is:
 1. A data storage device comprising: a first memorysection including a reserved area having stored therein an event triggerlog comprising a history of past logged events; a second memory sectionseparate from the first memory section; and a controller configured to:upon power up of the data storage device and before the data storagedevice is ready to receive host commands, allocate a buffer in thesecond memory section for capturing new events; and postpone linking ofany captured new events with the past logged events until at least afterthe data storage device is ready to receive the host commands.
 2. Thedata storage device of claim 1 and wherein the controller is configuredto link the captured new events with the past logged events when thedata storage device enters into an idle state.
 3. The data storagedevice of claim 1 and wherein the controller is configured to link thecaptured new events with the past logged events in response to an eventtrigger log request from a host.
 4. The data storage device of claim 1and wherein the controller is configured to link the captured new eventswith the past logged events before a power down of the data storagedevice.
 5. The data storage device of claim 1 and wherein the controlleris configured to set a new events flag in the buffer upon storing aninitial event or first event in the buffer.
 6. The data storage deviceof claim 5 and wherein, when the new events flag is set, the controlleris configured to link the captured new events with the past loggedevents: when the data storage device enters into an idle state; or inresponse to an event trigger log request from a host; or before a powerdown of the data storage device.
 7. The data storage device of claim 1and wherein the first memory section is a part of a first memory and thesecond memory section is a part of a second memory that is of adifferent memory type than the first memory.
 8. The data storage deviceof claim 7 and wherein the first memory is a data storage disc andwherein the second memory is a solid state memory.
 9. A methodcomprising: storing, by a control circuit of a data storage device, anevent trigger log comprising a history of past logged events of the datastorage device in a reserved area included in a first memory section ofthe data storage device; upon power up of the data storage device andbefore the data storage device is ready to receive host commands,allocating a buffer in a second memory section, of the data storagedevice, for capturing new events in the data storage device; andpostponing linking of any captured new events with the past loggedevents until at least after the data storage device is ready to receivethe host commands.
 10. The method of claim 9 and further comprisinglinking the captured new events with the past logged events when thedata storage device enters into an idle state.
 11. The method of claim 9and further comprising linking the captured new events with the pastlogged events in response to an event trigger log request from a host.12. The method of claim 9 and further comprising linking the capturednew events with the past logged events before a power down of the datastorage device.
 13. The method of claim 9 and further comprising settinga new events flag in the buffer upon storing an initial event or firstevent in the buffer.
 14. The method of claim 13 and wherein, when thenew events flag is set, linking the captured new events with the pastlogged events: when the data storage device enters into an idle state;or in response to an event trigger log request from a host; or before apower down of the data storage device.
 15. The method of claim 9 andwherein the first memory section is a part of a first memory and thesecond memory section is a part of a second memory that is of adifferent memory type than the first memory.
 16. The method of claim 15and wherein the first memory is a data storage disc and wherein thesecond memory is a solid state memory.
 17. A data storage devicecomprising: a system memory; a controller configured to: upon power-onreset of the data storage device and before the data storage device isready to receive host commands, allocate a buffer in the system memoryfor capturing new events; and link any captured new events with pastlogged events after the data storage device is ready to receive the hostcommands.
 18. The data storage device of claim 17 and wherein thecontroller is configured to link the captured new events with the pastlogged events when the data storage device enters into an idle state.19. The data storage device of claim 17 and wherein the controller isconfigured to link the captured new events with the past logged eventsin response to an event trigger log request from a host.
 20. The datastorage device of claim 17 and wherein the controller is configured tolink the captured new events with the past logged events before a powerdown of the data storage device.